• Bulletin of the Korean Chemical Society
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• 제22권12호
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• pp.1345-1349
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• 2001

New quadruply-bridged calix[6]arenes (I-V) have been studied as cesium selective ionophores in poly(vinyl chloride) (PVC) membrane electrodes. PVC membranes were prepared with dioctyl sebacate (DOS) or 2-nitrophenyl octyl ether (o-NPOE) as the sol vent mediator and potassium tetrakis(p-chlorophenyl)borate as the lipophilic salt additive. These ionophores produced electrodes with near-Nernstian slope. The selectivity coefficients for cesium ion with respect to alkali, alkaline earth and ammonium ions have been determined. The lowest detection limit (logaCs+ = -6.3) and the higher selectivity coefficient (logkpotCs+,Rb+ = -2.1 by SSM, -2.3 by FIM for calix[6]arene I) for Cs+ have been obtained for membranes containing quadruply-bridged calix[6]arenes (I, Ⅱ, Ⅲ), which have no para t-butyl substituents on the bridging benzene ring.

• Nuclear Engineering and Technology
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• 제47권7호
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• pp.867-874
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• 2015

Separation of cesium chloride (CsCl) and strontium chloride ($SrCl_2$) from the lithium chloride-potassium chloride (LiCl-KCl) salt was studied using a melt crystallization process similar to the reverse vertical Bridgeman growth technique. A ternary $SrCl_2-LiCl-KCl$ salt was explored at similar growth rates (1.8-5 mm/h) and compared with CsCl ternary results to identify similarities. Quaternary experiments were also conducted and compared with the ternary cases to identify trends and possible limitations to the separations process. In the ternary case, as much as 68% of the total salt could be recycled per batch process. In the quaternary experiments, separation of Cs and Sr was nearly identical at the slower rates; however, as the growth rate increased, $SrCl_2$ separated more easily than CsCl. The quaternary results show less separation and rate dependence than in both ternary cases. As an estimated result, only 51% of the total salt could be recycled per batch. Furthermore, two models have been explored to further understand the growth process and separation. A comparison of the experimental and modeling results reveals that the nonmixed model fits reasonably well with the ternary and quaternary data sets. A dimensional analysis was performed and a correlation was identified to semipredict the segregation coefficient.

• 공업화학
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• 제18권1호
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• pp.36-40
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• 2007

헤테로폴리산 촉매를 이용하여 endo-tetrahydrodicyclopentadiene 및 endo-tetrahydrodi(methylcyclopentadiene)의 이성화반응에 관한 연구를 행하였다. 이성화반응에 의해 endo 형태를 exo 형태의 화합물로 제조하였다. 기존의 이성화촉매인 알루미늄 클로라이드의 문제점을 개선하기 위하여 헤테로폴리산의 적용을 시도하였다. Keggin 형태의 헤테로폴리산 촉매인 $H_3PW_{12}O_{40}$에서 수소원자 2.5개 대신에 cesium으로 치환시 촉매활성이 가장 높았다. Cesium으로 치환된 헤테로폴리산 촉매 사용시 기존의 알루미늄클로라이드 촉매보다 이성화반응속도가 빠른 것을 확인하였고, 반응온도, 시간에 따른 tetrahydrodicyclopentadiene 및 tetrahydrodi(methylcyclopentadiene)의 반응성을 비교하였다.

• 대한환경공학회지
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• 제38권1호
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• pp.8-13
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• 2016

본 연구에서는 물속에 존재하는 방사성 세슘($Cs^+$)의 정수처리 제거방법을 고찰하였다. 세슘은 물속에서 대부분 이온상태인 $Cs^+$로 존재하여 모래여과, 정수약품(PACl), 분말활성탄(PAC) 및 정수약품(PACl + PAC) 혼합주입에 의해 제거되지 않았으나 탁도가 증가함에 따라 세슘 제거율이 증가하는 것으로 나타났다. G-취수장 주변 고형물과 황토를 이용하여 탁도를 각각 74 NTU와 103 NTU로 조정했을 때 세슘의 제거율은 각각 약 56%, 51%이었으며 상징수를 GAC로 여과한 경우, 세슘의 약 80%가 제거되었다. 따라서 효과적인 세슘 제거를 위해서는 황토 등을 이용하여 원수 탁도를 80 NTU 이상 조정해야 하는 것으로 나타났다. GAC에 의한 세슘 제거의 경우, 약 60%가 제거됨을 알 수 있었으며 이것은 접촉에 따른 흡착에 의해 제거된 것으로 판단된다. 막에 의한 세슘 제거에 있어서 정밀여과막으로는 제거되지 않았으나 역삼투막에서는 75%가 제거되었다.

• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2867-2872
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• 2010

Two new energetic organic alkali metal salts, 1,1-diamino-2,2-dinitroethylene rubidium salt [Rb(FOX-7)${\cdot}H_2O$] and 1,1-diamino-2,2-dinitroethylene cesium salt [Cs(FOX-7)${\cdot}H_2O$], were synthesized by reacting of 1,1-diamino-2,2-dinitroethylene (FOX-7) and rubidium chloride or cesium chloride in alkali methanol aqueous solution, respectively. The thermal behaviors of Rb(FOX-7)${\cdot}H_2O$ and Cs(FOX-7)${\cdot}H_2O$ were studied with DSC and TG methods. The critical temperatures of thermal explosion of the two compounds are 216.22 and $223.73^{\circ}C$, respectively. Specific heat capacities of the two compounds were determined with a micro-DSC method, and the molar heat capacities are 217.46 and $199.47\;J\;mol^{-1}\;K^{-1}$ at 298.15 K, respectively. The adiabatic times-to-explosion were also calculated to be a certain value of 5.81 - 6.36 s for Rb(FOX-7)${\cdot}H_2O$, and 9.92 - 10.54 s for Cs(FOX-7)${\cdot}H_2O$. After FOX-7 becoming alkali metal salts, thermal decomposition temperatures of the compounds heighten with the rise of element period, but thermal decomposition processes become intense.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제25회 추계학술대회논문집
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• pp.229-232
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• 2005

인화점이 높은 합성 액체연료인 RJ-4의 제조공정 개선에 관한 연구를 수행하였다. 상용원료인 MCPD(Methylcyclopentadiene dimer)를 이용한 RJ-4 연료제조에서 헤테로폴리 텅스토인산 세슘염 촉매와 2단 열 조절반응기를 사용하여 1차, 2차 수소화 및 이성화반응이 1 단계 연속공정으로 가능함을 알 수 있었다. 또한 $AlCl_3$ 대신에 헤테로폴리산 세슘염을 이성화촉매로 사용시 exe-THDMCPD(Tetrahydrodimethylcyclopentadiene)을 얻는 속도가 더 빠르며, 생성물과의 분리가 용이하고, 폐산 발생이 없으므로 환경친화적인 공정임을 확인하였다.

• The Korean Journal of Physiology
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• 제26권1호
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• pp.27-35
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• 1992

We used the whole cell patch clamp technique to examine the ionic basis for the tail current after depolarizing pulse in single atrial myocytes of the rabbit. We recorded the tail currents during various repolarizations after short depolarizing pulse from a holding potential of -70 mV. The potassium currents were blocked by external 4-aminopyridine and replacement of internal potassium with cesium. The current was reversed to the outward direction above +10 mV. High concentrations of intracellular calcium buffer inhibited the activation of the current. Diltiazem and ryanodine blocked it too. These data suggest that the current is activated by intracellular calcium released from sarcoplasmic reticulumn. When the internal chloride concentration was increased, the inward tail current was increased. The current was partially blocked by the anion transport blocker niflumic acid. The current voltage curve of the niflumic acid sensitive current component shows outward rectification and is well fitted to the current voltage curve of the theoretically predicted chloride current calculated from the constant field equation. The currents recorded in rabbit atrial myocytes, with the method showing isolated outward Na Ca exchange current in ventricular cells of the guinea pig, suggested that chloride conductance could be activated with the activation of Na/ca exchange current. From the above results it is concluded that a chloride sensitive component which is activated by intracellular calcium contributes to tail currents in rabbit atrial cells.

• 대한수의학회지
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• 제34권1호
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• pp.25-36
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• 1994

The inward tail current after a short depolarizing pulse has been known as Na-Ca exchange current activated by intracellular calcium which forms late plateau of the action potential in rabbit atrial myocytes. Chloride conductance which is also dependent upon calcium concentration has been reported as a possible tail current in many other excitable tissues. Thus, in order to investigate the exsitance of the calcium activated chloride current and its contribution to tail current, whole cell voltage clamp measurement has been made in single atrial cells of the rabbit. The current was recorded during repolarization following a brief 2 ms depolarizing pulse to +40mV from a holding potential of -70mV. When voltage-sensitive transient outward current was blocked by 2 mM 4-aminopyridine or replacement potassium with cesium, the tail current were abolished by ryanodine$(1{\mu}M)$ or diltiazem$(10{\mu}M)$ and turned out to be calcium dependent. The magnitudes of the tail currents were increased when intracellular chloride concentration was increased to 131 mM from 21 mM. The current was decreased by extracellular sodium reduction when intracellular chloride concentration was low(21 mM), but it was little affected by extracellular sodium reduction when intracellual chloride concentration was high(131 mM). The current-voltage relationship of the difference current before and after extracellular sodium reduction, shows an exponential voltage dependence with the largest magnitude of the current occurring at negative potentials, with is similar to current-voltage relationship at negative potentials, which is similar to current-voltage relationship of Na-Ca exchange current. The current was also decreased by $10{\mu}M$ niflumic acid and 1 mM bumetanide, which is well known anion channel blockers. The reversal potentials shifted according to changes in chloride concentration. The current-voltage relationships of the niflumic acid-sensitive currents in high and low concentration of chloride were well fitted to those predicted as chloride current. From the above results, it is concluded that calcium activated chloride component exists in the tail current with Na-Ca exchange current and it shows the reversal of tail current. Therefore it is thought that in the physiologic condition it leads to rapid end of action potential which inhibits calcium influx and it contributes to maintain the low intracellular calcium concentration with Na-Ca exchange mechanism.

• Macromolecular Research
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• 제13권2호
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• pp.141-146
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• 2005

Calix[4]crown-6-2,4-bis(4-aminobutyl ether), which has a crown-6 moiety at the 1,3-position and amino function at the 2,4-position, was prepared as an intermediate for the subsequent synthesis of calix[4]crown-6-containing polyamide and polyimide using adipoyl chloride and 1,2,4,5-benzenetetracarboxylic dianhydride. The chemical structures were characterized by IR, $^{1}H NMR$ spectroscopy and elemental analysis, and some of their physical properties, including their thermal behavior, were examined. The ion binding characteristics of the monomer and polymers for alkali metal and alkali earth metal ions were measured by liquid-liquid extraction from the aqueous phase into the organic phase. It has been observed that polyamide has a high binding ability towards various metal cations as compared to polyimide, which showed cesium ion selectivity.

• BMB Reports
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• 제34권5호
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• pp.478-483
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• 2001

We examined the effect of CsCl and spermine on the induction of ornithine decarboxylase (ODC), a key enzyme in polyamine synthesis form Glycine max axes. Transcription of the ODC gene was induced by 0.1 and 1 mM of CsCl, and the amount of putrescine was increased 3.5-fold by 1 mM CsCl treatment. Spermine also induced the expression of the ODC gene in a die dependent manner. However, CsCl provoked an increase in the active phosphorylated ERK (pERK), a central element of the mitogen-activated protein kinase (MAPK) cascade. Our data demonstrates an interaction between the ODC induction and the MAPK signaling pathway, and suggests that the latter may be involved in cell signaling in salt-stressed plants.